It is a SAD fact that the general prognosis for a late-stage (stage 4) lung cancer patient is not very good at all. Although, it should be noted at this point, some late-stage patients do seem to pull something out of the hat and respond well to treatment (in general, when talking about late-stage lung cancer, it is usually assumed to be non-small cell [NSCLC] - the most commonly diagnosed type)

NSCLC is usually responsible for 80% + of all cases diagnosed, whereas small cell lung cancer (SCLC) is usually only responsible for under 20% of cases(SCLC is the least common and more deadly of the two types). Mixed cell/large cell lung cancer is a mixture of both SCLC and NSCLC.

Stage 4 - indicates that the cancer has metastasized from its origin to another part/s of the body (outside of the chest area). However, sometimes certain situations will arise in its development that allows for a patient to have a better out-come (usually only with NSCLC patients). For example:

When the metastasis of the cancer is limited in size and number, it may be possible to treat it with modern aggressive directed treatments.

When bronchioloaveloar (BAC) is present in a patient (a type of non-small lung cancer), due to it being very slow-growing - often a patient can be monitored without the need for treatment (sometimes for many years).

Where non-small lung cancer is present, molecular testing is usually carried-out to determine ALK mutations (mutations in the ALK gene change single protein building blocks [amino acids] in anaplastic lymphoma kinase - 5% of patients are usually affected), and EGFR ([epidermal growth factor receptor] 15% of patients are usually affected). TKI([s] medicine may be used to target the mutations for a prolonged control of the cancer (Xalkori and Tarceva).

Under certain circumstances, a patient may have late stage NSCLC that is sensitive to chemotherapy (prolonging prognosis [life-expectancy] due to the treatment being more successful).

However, in general, a stage 4 NSCLC diagnosis will mean a short prognosis (related factors to an individuals prognosis [taken on a one by one basis] include: age, general health, treatment choice and response, and the characteristics of the tumor). But, as a general rule-of-thumb, the following could be considered to be normal in most cases:

Non-small cell lung cancer (stage 4) - low prognosis (only 10% - 15% of sufferers will be seen to still be alive 5-years after diagnosis).

Small-cell lung cancer (stage 4) - very low prognosis (only 5% - 10% of sufferers will still be seen to be alive 5-years after diagnosis [2 - 4-months if left untreated]).